Hello, i have a 2005 Alfa Romeo 156 2.0 JTS Veloce and have a problem with the on board computer message " ENGINE CONTROL SYSTEM FAILURE", "GO TO DEALER", i took it to my local garage and they said it needed a thermostat, when i collected the car with the new thermostat fitted the warning message was gone, however it is now three weeks later and the warning message has come back on,
I think the car is running a little cold, the temperature guage never gets above 75 degrees, even after a recent 200 mile journey, the car seems to be running fine (no power loss), can anyone help, thanks Eddie

I think the car is running a little cold, the temperature guage never gets above 75 degrees, even after a recent 200 mile journey, the car seems to be running fine (no power loss), can anyone help, thanks Eddie

Hello mate, apart from not having the error my temp gauge was like that before i had a new stat fitted yesterday, but now its running up to temp properly. I was having power loss before the replacement though. Im sure someone technical on here can help but i think you might have to get the garage to run diagnostics again to see whats bringing up the fault.

Edit: I did have an error once recently i remember and it turned out to be the Cat but when they did an emissions test it was fine. Its possible your CAT has overheated and brought up the fault. Im wondering if the stat they fitted was a faulty one... as the 75 degrees problem seems a common one for a stat thats permanently open.

Cheers for your reply, but a new temperature sensor seems to have cracked it, within a few minutes the temerature gauge went up to 90ish and stayed there, and the garage laptop prior to changing the sensor said the actual engine temp was 89 degrees, so it seems the faulty sensor was making the gauge read 75 degrees and confusing the brain into thinking the car was running cold.